"Leetcode" 67. ADD Binary

Title:

Given binary strings, return their sum (also a binary string).

For example,
A ="11"
b ="1"
Return "100" .

Tips:

My first reaction to this question is to convert the input two string into a number, add the result into a binary output, but there will be a lot of input in the test case, even if a long long type can also cause overflow, so can only use the most traditional from low to high position to add the method to do.

Code:

classSolution { Public:    stringAddbinary (stringAstringb) {intLen_a = A.size ()-1, Len_b = B.size ()-1; intDIF = ABS (Len_a-Len_b); stringPrev ="";  for(inti =0; i < dif; ++i) Prev + ='0'; if(Len_a < Len_b) A = prev +A; Elseb = prev +b; intLen = a.size (), step =0; Vector<int>v;  for(inti = len-1; I >-1; --i) {step+ = A[i] + b[i]-('0'<<1); V.push_back (Step%2); Step= Step >>1; }        if(step) v.push_back (step%2); stringRes;  for(inti = v.size ()-1; I >-1; --i) {res+= ('0'+V[i]); }        returnRes; }};

"Leetcode" 67. ADD Binary